Self-driving travel bag

China’s ForwardX Robotics demonstrated at CES 2018 a four-wheeled travel bag that automatically follows its user around the airport. The smart bag uses cameras and AI to avoid crashes. The device can message the owner if it gets too far away or when the battery power gets low.

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With a max speed of up to 7 miles per hour, this piece of high-tech luggage offers up to four hours of battery life on a charge, and it can also juice your gadgets using a built-in mobile charger. The company says the battery is removable, if you’re concerned about airlines cracking down on checking anything with Lithium-ion batteries.

Cheaper LEDs

Computers have helped researchers develop a new phosphor that can make LEDs cheaper and render colors more accurately. Researchers predicted the new phosphor using supercomputers and data mining algorithms, then developed a simple recipe to make it in the lab. Unlike many phosphors, this one is made of inexpensive, earth-abundant elements and can easily be made using industrial methods. As computers predicted, the new phosphor performed well in tests and in LED prototypes.

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Phosphors, which are substances that emit light, are one of the key ingredients to make white LEDs. They are crystalline powders that absorb energy from blue or near-UV light and emit light in the visible spectrum. The combination of the different colored light creates white light. The phosphors used in many commercial white LEDs have several disadvantages, however. Many are made of rare-earth elements, which are expensive, and some are difficult to manufacture. They also produce LEDs with poor color quality.

The new phosphor — made of the elements strontium, lithium, aluminum and oxygen (a combination dubbed “SLAO”) — was discovered using a systematic, high-throughput computational approach developed in the lab of Shyue Ping Ong, a nanoengineering professor at the UC San Diego Jacobs School of Engineering and lead principal investigator of the study. Ong’s team used supercomputers to predict SLAO, which is the first known material made of the elements strontium, lithium, aluminum and oxygen. Calculations also predicted this material would be stable and perform well as an LED phosphor. For example, it was predicted to absorb light in the near-UV and blue region and have high photoluminescence, which is the material’s ability to emit light when excited by a higher energy light source.

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Butterfly wing inspired photovoltaics

Sunlight reflected by solar cells is lost as unused energy. The wings of the butterfly Pachliopta aristolochiae are drilled by nanostructures (nanoholes) that help absorbing light over a wide spectrum far better than smooth surfaces. Researchers have now succeeded in transferring these nanostructures to solar cells and, thus, enhancing their light absorption rate by up to 200 percent.

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“The butterfly studied by us is very dark black. This signifies that it perfectly absorbs sunlight for optimum heat management. Even more fascinating than its appearance are the mechanisms that help reaching the high absorption. The optimization potential when transferring these structures to photovoltaics (PV) systems was found to be much higher than expected,” says Dr. Hendrik Hölscher of KIT’s Institute of Microstructure Technology (IMT). The scientists  reproduced the butterfly’s nanostructures in the silicon absorbing layer of a thin-film solar cell. Subsequent analysis of light absorption yielded promising results: Compared to a smooth surface, the absorption rate of perpendicular incident light increases by 97% and rises continuously until it reaches 207% at an angle of incidence of 50 degrees.

Prior to transferring the nanostructures to solar cells, the researchers determined the diameter and arrangement of the nanoholes on the wing of the butterfly by means of scanning electron microscopy. Then, they analyzed the rates of light absorption for various hole patterns in a computer simulation. They found that disordered holes of varying diameters, such as those found in the black butterfly, produced most stable absorption rates over the complete spectrum at variable angles of incidence, with respect to periodically arranged monosized nanoholes. Hence, the researchers introduced disorderly positioned holes in a thin-film PV absorber, with diameters varying from 133 to 343 nanometers.

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3-D images floating in thin air

Brigham Young University’s electrical and computer engineering professor and holography expert Daniel Smalley has long had a goal to create a type of 3D image projection, like the one from the Star Wars film, where R2D2 projects an image of Princess Leia in distress. The iconic scene includes the line still famous 40 years later: “Help me Obi Wan Kenobi, you’re my only hope.”

“We refer to this colloquially as the Princess Leia project,” Smalley said. “Our group has a mission to take the 3D displays of science fiction and make them real. We have created a display that can do that.” First things, first, Smalley says. The image of Princess Leia is not what people think it is: It’s not a hologram. A 3D image that floats in air, that you can walk all around and see from every angle, is actually called a volumetric image. Examples of volumetric images include the 3D displays Tony Stark interacts with in Ironman or the massive image-projecting table in Avatar. A holographic display scatters light only at a 2D surface. If you aren’t looking at that surface you won’t see the 3D image because you must be looking at the scattering surface to see the image. A volumetric display has little scattering surfaces scattered throughout a 3D space — the same space occupied by the 3D image — so if you are looking at the image you’re are also looking at the scatters. For this reason, a volumetric image can be seen from any angle.

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Smalley and his coauthors have devised a free -space volumetric display platform, based on photophoretic optical trapping, that produces full-color, aerial volumetric images with 10-micron image points by persistence of vision. “We’re using a laser beam to trap a particle, and then we can steer the laser beam around to move the particle and create the image,” said undergrad coauthor Erich Nygaard. Smalley said the easiest way to understand what they are doing is to think about the images they create like 3D-printed objects. “This display is like a 3D printer for light,” Smalley said. “You’re actually printing an object in space with these little particles.”

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